Default My files got deleted

I need some help because I had some important files in my phone (such as fotos and documents) which got deleted I dunno why!
I was tranfering some music to the phone via USB cable and then I erased a folder with strange characters (I mean ".FHniod555dsniosd" something like that). Well, the connection was interupted and I had to remove the USB cable from the phone. Then I noticed all my files had been deleted.

Can I recover the files? How? What did I do wrong to cause this? The folder was empty :|